KR20070113077A - Optical film, optical filter and display devices comprising the same - Google Patents

Abstract

An optical film, and an optical filter and a display device having the optical film are provided to improve a color representation performance of the display device by selectively cutting yellow light with a wavelength between 470 and 510nm. An optical film includes a transparent substrate(10) and a selective visual ray absorbing layer(20). The selective visual ray absorbing layer contains at least one dye having a maximum absorbing wavelength between 470 and 510nm. The selective visual ray absorbing layer is formed on the transparent substrate. A maximum transmittance of the selective visual ray absorbing layer at the maximum absorbing wavelength of the dye is lower than 60%. An FWHM(Full Width at Half Maximal) of the selective visual ray absorbing layer lies between 10 and 60nm.

Description

Optical film, optical filter and display device including the same {OPTICAL FILM, OPTICAL FILTER AND DISPLAY DEVICES COMPRISING THE SAME}

1 is a schematic cross-sectional view of an optical film according to an embodiment of the present invention.

2 is a graph illustrating a comparison of light transmittances of optical films manufactured in Examples and Comparative Examples.

* Description of the symbols for the main parts of the drawings *

10: transparent substrate 20: selective visible light absorbing layer

The present invention relates to an optical film, an optical filter and a display device including the same, and more particularly, at least one pigment having a maximum absorption wavelength in the 470 ~ 510nm band, the maximum value of the light transmittance of the maximum absorption wavelength An optical film comprising a selective visible light absorbing layer having a maximum value of 60% or less and a half maximum width of an absorption maximum of 10 to 50 nm, and an optical filter and a display device including the same.

Liquid Crystal Display, Plasma Display Panel, Electro-Luminescence Display and Field Emission Display Flat panel displays (FPDs), such as (Field Emission Display) and Fluorescent Fluorescent Display, are in the spotlight.

However, as an example, a plasma display emits a large amount of near infrared rays when the discharge gas emits ultraviolet rays to emit phosphors. The near-infrared generated at this time may cause malfunctions of various electronic devices using the near-infrared, for example, a remote control device of a home appliance or a near-infrared communication device such as a computer or a wireless telephone.

In order to solve this problem, in the prior art, an optical film using an anthraquinone-based, phthalocyanine-based, dithiol-metal complexing system, diimmonium-based dye, etc., absorbing near infrared rays in the wavelength range of 820 to 1000 nm has been developed. No. 1998-139997, Korean Patent Publication No. 2000-5531 and Korean Patent Publication No. 2004-20982).

In addition, since the plasma display uses neon gas as a penning gas for exciting the phosphor, orange neon light is emitted in the vicinity of 585 nm, thereby degrading green and red color purity. In order to solve this problem, a color correction film which obtains red and green light having high color purity by selectively cutting neon light in the visible light region of 580 to 600 nm using a tetraazaporphyrin dye or a cyanine dye It was also developed (Japanese Patent Application Laid-Open No. 2000-27543 and US Patent No. 6,532,120).

In recent years, yellow-based light emitted by the penning gas in the vicinity of 470-510 nm has become a problem as a factor of lowering the color purity. Such yellow light has a problem of degrading the color purity of blue and green on the display, thereby degrading the image quality of the display device.

The present invention is to overcome the problems of the prior art described above, one object of the present invention is to provide an optical film that can improve the color purity and color reproducibility by effectively cutting the yellow light generated in the 470 ~ 510nm band .

Another object of the present invention is to provide an optical filter capable of effectively cutting yellow light generated in the 470 to 510 nm band to improve color purity and color reproducibility.

Still another object of the present invention is to provide a display device having improved color purity and color reproducibility including the optical filter of the present invention.

One aspect of the present invention for achieving the above object is

Transparent substrates; And

And a selective visible light absorbing layer containing at least one dye having a maximum absorption wavelength in the 470-510 nm band formed on the transparent substrate, wherein the selective visible light absorbing layer has a maximum value of light transmittance at the maximum absorption wavelength of the dye. It is 60% or less, and the maximum value width (FWHM) of an absorption maximum is 10-50 nm, It is related with the optical film characterized by the above-mentioned.

The optical film of the present invention can be prepared by laminating a coating liquid containing a dye, a binder resin and a solvent on a transparent substrate. The dye is preferably a cyanine-based dye, has a maximum absorption wavelength in the 470 ~ 510nm band, more preferably has a maximum absorption wavelength in the 485 ~ 495 nm band.

The selective visible light absorbing layer is at least one selected from the group consisting of an anthraquinone dye, a perinone dye, a monoazo dye, a disazo dye, and a methine dye in addition to the dye. It may further comprise color tone pigments.

Another aspect of the present invention for achieving the above object relates to an optical filter comprising the optical film of the present invention.

Another aspect of the present invention for achieving the above object relates to a display device comprising the optical filter of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Optical film of the present invention is a transparent substrate; And an optional visible light absorbing layer containing at least one dye having a maximum absorption wavelength in the range of 470 to 510 nm formed on the transparent substrate, wherein the selective visible light absorbing layer has a maximum value of light transmittance at a maximum absorption wavelength of the dye. It is 60% or less, It is characterized by the absorption maximum half value width (FWHM) of 10-50 nm.

1 is a schematic cross-sectional view of an optical film according to an embodiment of the present invention. Referring to FIG. 1, the optical film of the present invention includes a transparent substrate 10 and an optional visible light absorbing layer 20 stacked thereon. The selective visible light absorbing layer 20 dissolves one or more pigments (hereinafter referred to as "selective visible light absorbing dyes") having a maximum absorption wavelength in the band of 470 to 510 nm in a binder solution composed of a binder resin and a solvent. The dispersed coating liquid may be prepared by laminating on the transparent substrate 10.

Preferably the selective visible light absorbing dye has a maximum absorption wavelength in the 470 ~ 510nm band, more preferably a maximum absorption wavelength in the region of 485 ~ 495 nm, a preferred example of such a dye includes a cyanine pigment do.

Examples of such cyanine pigments include, but are not necessarily limited to, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, and the like. Specific examples of the cyanine-based pigments that can be used in the present invention include GPX 102 manufactured by Asahi Denki Co., Ltd., GPX 201, NK-4271 manufactured by Hayashibara Biochemical Co., Ltd., and NK-7803.

In the present invention, the light transmittance of the maximum absorption wavelength of the selective visible light absorbing layer 20 is preferably 60% or less. When the maximum value of the maximum absorption wavelength exceeds 60%, it becomes impossible to absorb yellow light, which lowers the color purity, and thus the object of the present invention cannot be achieved. More preferably, the selective visible light absorbing layer 20 has a maximum light transmittance of 50% or less at the maximum absorption wavelength.

In addition, the selective visible light absorbing layer 20 has a half width at the absorption maximum of 10 to 50 nm. In the present invention, the term "full width at half maximal" means a wavelength bandwidth between two points at a point that is half the maximum value of the transmittance of the light transmittance curve of the optical film of the present invention. In the present invention, when the half maximum width of the absorption maximum of the selective visible light absorbing layer 20 exceeds 50 nm, the selective visible light absorbing layer 20 is formed of red, blue, and green light emitting phosphors. ), Green (G) and blue (B) affect the visible light, making it difficult to achieve vivid colors and reducing the resolution of the screen. On the other hand, in the present invention, when the half maximum width of the absorption maximum of the selective visible light absorbing layer 20 is less than 10 nm, the difficulty of the technique for implementing such characteristics is beyond practical advantage obtained by such characteristics.

In the present invention, the selective visible light absorbing layer 20 preferably contains 0.0001 to 20 parts by weight of the selective visible light absorbing pigment with respect to 100 parts by weight of the total solids, more preferably 0.001 to 10 parts by weight.

In the present invention, the binder resin constituting the selective visible light absorbing layer 20 is a resin which is cured or dried by applying energy such as heat, ultraviolet rays, electron beams, melamine resin, urethane resin, epoxy resin, polyester resin, poly One or more types of ether resin, polyimide resin, silicone resin, and acrylic resin can be used.

In the present invention, the binder resin preferably contains 10 to 90 parts by weight based on 100 parts by weight of the total solids.

In the present invention, the selective visible light absorbing layer 20 may further include a color tone dye for adjusting the color of the optical film in addition to the selective visible light absorbing dye.

The color tone pigments that can be used may vary depending on the color to be expressed. The color tone pigments usable in the present invention may be an anthraquinone pigment, a perinone pigment, a monoazo pigment, or a disazo ( Disazo) -based pigments and methine-based may include one or more selected from the group consisting of. Such color tone dyes may be used alone or in combination of two or more. Preferred examples of the color tone pigments include anthraquinone pigments represented by the following Chemical Formulas 1 to 5, Perinone pigments represented by Chemical Formula 6, and methine pigments represented by Chemical Formula 7.

In addition, as the anthraquinone pigments, commercially available aminoanthraquinone pigments such as Green-5B, Blue-RR, Redvio-RV, Violet-R, and Green-G manufactured by Emdomen Corporation may be used, and perinone pigments. As the Emdomen company Red A2G and the like can be used. As the disazo-based pigment, commercially available MDO Men's Black series Black KB, Black K and Yabang's Yellow 93 (C ₂₁ H ₁₈ N ₄ O ₂ ) and the like can be used.

 In the case where the selective visible light absorbing layer 20 further includes a color crystal dye, the content of the color crystal dye is preferably 0.0001 to 30 parts by weight, more preferably 0.001 to 15 parts by weight based on 100 parts by weight of the total solid. It is wealth.

In the optical film of the present invention, the transparent substrate 10 serves as a support for the selective visible light absorbing layer 20, and is not particularly limited as long as it has transparency to visible light. For example, the transparent substrate 10 may include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefins such as cyclic polyolefin, polyethylene, polypropylene, and polystyrene, polyvinyl chloride, and polychloride. It may be a vinyl resin such as vinylidene, polycarbonate, acrylic resin, triacetyl cellulose (TAC), polyethersulfone, or polyether ketone resin film.

The optical film of the present invention can be produced using any method known in the art. For example, in the optical film, the selective visible light absorbing layer 20 is added to a solvent, mixed with a selective visible light absorbing dye, a binder resin, and other additives added as needed, and dissolved or dispersed in each component to make selective visibility. After preparing a coating solution for forming a light absorption layer, it may be formed by applying it to a transparent substrate and drying.

The solvent is methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), acetone (Acetone), cyclohexanone (Cyclohexanone), ketone compounds such as cyclopentanone (Cyclopentanone), dioxolane (dioxolane), dioxin One or more of ether compounds such as (Dioxane) and dimethoxyethane and aromatic compounds such as toluene and xylene may be used.

In addition, as the other additives, an antioxidant or an ultraviolet absorber for improving the durability of the selective visible light absorbing layer 20 may be added. As antioxidant, phenol, amine, hindered phenol, hindered amine, sulfur, phosphoric acid, phosphorous acid, or metal complex type antioxidant can be used. As ultraviolet absorber, benzophenone, Or a benzotriazole type ultraviolet absorber can be used.

Alternatively, the selective visible light absorbing pigment and the transparent binder resin may be prepared by applying a coating solution obtained by melt-kneading together with other additives to a transparent substrate while melt extrusion.

As a method of applying the coating liquid for forming the selective visible light absorbing layer, spin coating, roll coating, mayaba coating, doctor blade coating, gravure coating, gravure reverse coating, kiss reverse coating, die coating, or commer Various coating methods, such as a coating method, can be used.

The optical film of the present invention may be included in optical filters of various display devices. Such an optical filter may include one or more of a separate near-infrared absorbing layer, an electromagnetic wave shielding layer, a color tone adjusting layer, a neon light shielding layer, an antifouling layer, an antireflection layer, and an adhesive layer in addition to the optical film of the present invention. According to this, the functions of each layer may be composed of a composite layer. For example, it may include one layer that blocks both near infrared rays and neon light.

In another aspect, the present invention relates to a display device comprising the optical film or optical filter described above. The display device may be a plasma display device as an example, but is not limited thereto, and may be applied to other types of display devices such as a liquid crystal display.

The optical filter of the present invention is mainly applied to the front of the plasma display device to selectively absorb the visible light in the wavelength range of 470-510 nm generated when the plasma display device emits light using neon, xenon gas and other gas discharge plasma It improves the color purity of the display device, in particular the blue and green color purity and color reproducibility, ultimately improve the image quality.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for explaining the preferred embodiment of the present invention, the scope of the present invention is not limited by the following examples.

Example 1

As a cyanine pigment, 0.03g of GPX 201, a pigment of Asahi Denka, is mixed with 31.97g of methyl ethyl ketone, stirred until the pigment is sufficiently dissolved, and 68g of Halshybrid IR-G 205 from Nippon Shokubai is added. After sufficiently stirring to prepare a coating solution for forming a selective visible light absorbing layer. The coating solution was spin coated on a transparent substrate (Toyobo PET film A4100) and dried at 80 ° C. for 1 minute to prepare an optical film.

Example 2

As a cyanine pigment, 0.05 g of GPX 201, a pigment of Asahi Denka, and 0.16 g of Blue RR, a dye of M.Dohmen, were mixed with 31.79 g of methyl ethyl ketone, and stirred until the pigment was sufficiently dissolved. After the addition of 68g Halshybrid IR-G 205 Nippon Shokubai Co., Ltd. was prepared in the same manner as in Example 1 except that the coating solution was prepared to produce an optical film.

Comparative Example 1

As a pigment | dye, it carried out similarly to Example 1 except having used 0.03g of Blue RR 0.04g, MK Dohmen, 0.02g of Black KB, and Yellow 93 by Yabang, and 31.91g of methyl ethyl ketones as a solvent. The optical film was prepared.

Comparative Example 2

An optical film was prepared in the same manner as in Example 1 except that 0.4 g of Red A2G manufactured by M. Dohmen was used as a dye and 31.6 g of methyl ethyl ketone was used as a solvent.

* Light transmittance measurement

The optical transmittances of the optical films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were measured using a spectrophotometer (Lamda 950 spectrophotometer manufactured by Perkin-Elmer) according to the wavelength. The maximum absorption wavelength, the transmittance at the maximum absorption wavelength, and the half maximum width of the absorption maximum in a specific wavelength region of 470 nm to 510 nm are shown in Table 1 below.

Absorption wavelength (nm) % Transmittance at maximum absorption wavelength Half width (nm) Example 1 494 47 38 Example 2 494 28 46 Comparative Example 1 494 76 19 Comparative Example 2 496 53 119

As confirmed through the results of Table 1, the optical films (Examples 1 and 2) of the present invention have a maximum absorption in the wavelength band of 470 ~ 510nm, the light transmittance at this maximum absorption wavelength is 60% Below, the half value width of absorption maximum belonged to the range of 10-50 nm.

Figure 2 shows the results as a graph, in the case of the optical film produced according to the present invention (Examples 1 to 2), it can be seen that the light of the wavelength band of 470 ~ 510nm very selective cut.

Since the optical film of the present invention can selectively cut yellow light in the wavelength range of 470 to 510 nm generated from the phosphor of the plasma display device, the display device including the optical film of the present invention is blue and green. It has a good balance and excellent color reproducibility.

Claims (13)

Transparent substrates; And an optional visible light absorbing layer containing at least one dye having a maximum absorption wavelength in the 470 to 510 nm band formed on the transparent substrate, wherein the selective visible light absorbing layer has a maximum value of a light transmittance of the maximum absorption wavelength of the dye. An optical film, characterized in that it is 60% or less, and the maximum absorption width (FWHM) is 10 to 50 nm. The optical film of claim 1, wherein the selective visible light absorbing layer has a maximum light transmittance of 50% or less at a maximum absorption wavelength. The optical film of claim 1, wherein the dye is a cyanine dye. The optical film of claim 1, wherein the dye has a maximum absorption wavelength in a region of 485 to 495 nm. The method of claim 1, wherein the selective visible light absorbing layer is 0.0001 to 20 parts by weight of the pigment based on 100 parts by weight of total solids; Optical film comprising 10 to 90 parts by weight of the binder resin. The method of claim 1, wherein the transparent substrate is polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclic polyolefin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, acrylic resin, Optical film, characterized in that selected from the group consisting of triacetyl cellulose (TAC), polyethersulfone (polyethersulfone) and polyether ketone resin film. The group of claim 1, wherein the selective visible light absorbing layer is formed of an anthraquinone pigment, a perinone pigment, a monooazo pigment, a disazo pigment, and a methine pigment, in addition to the pigment. An optical film, characterized in that it further comprises one or more color tone pigments selected from. 8. The optical film according to claim 7, wherein the color tone dye is at least one of dyes represented by the following general formulas (1) to (7). [Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

The method of claim 5, wherein the selective visible light absorbing layer is an anthraquinone pigment, a perinone pigment, a monoazo pigment, a disazo pigment and a methine based on 100 parts by weight of total solids Optical film, characterized in that it further comprises 0.0001 to 30 parts by weight of one or more color tone pigments selected from the group consisting of pigments. The method of claim 5, wherein the binder resin is at least one member selected from the group consisting of melamine resin, urethane resin, epoxy resin, polyester resin, polyether resin, polyimide resin, silicone resin and acrylic resin. An optical film, characterized in that. The optical film of claim 1, wherein the selective visible light absorbing layer is formed by coating a coating liquid including a dye, a binder resin, and a solvent on a transparent substrate. An optical filter comprising the optical film of claim 1. A display device comprising the optical filter of claim 12.

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